Hybrid distortion suppression system and method

This application is a continuation of International Patent Application No. PCT/US2020/063070, entitled, “Hybrid Distortion Suppression System and Method” and filed on Dec. 3, 2020, which claims benefit of U.S. Provisional Application No. 63/080,198, entitled, “Hybrid Distortion Suppression System and Method” and filed on Sep. 18, 2020, applications of which are hereby incorporated herein by reference in their entireties.

The disclosure generally relates to reducing distortions and improving power consumption in a radio transmitter and/or receiver, or more generally, a transceiver.

Wireless communication systems are widely used to provide voice and data services for multiple users using a variety of access terminals such as cellular telephones, laptop computers and various multimedia devices. Such communications systems can encompass local area networks, such as IEEE 801.11 networks, cellular telephone and/or mobile broadband networks. The communication system can use one or more multiple access techniques, such as Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA) and others. Mobile broadband networks can conform to a number of standards such as Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE) and the like.

A wireless network may include a wireless device and a plurality of base stations. The wireless device may be a notebook computer, a mobile phone or a Personal Digital Assistant (PDA), a media player, a gaming device or the like. The base stations communicate with the wireless device over a plurality of wireless channels coupled between the wireless device and the base stations (e.g., a downlink channel from a base station to a wireless device). The wireless device may send back information, including channel information, to the base stations over a plurality of feedback channels (e.g., an uplink channel from the wireless device to the base station).

The wireless device may include a processor, a transmitter and a receiver. The transmitter may be coupled to at least one transmit antenna. The receiver may be coupled to at least one receive antenna. The at least one transmit and at least one receive antenna may be the same or different antennas. One major function of the receiver is rejecting unwanted noise such as signals including harmonics from adjacent channels and, more generally interference so that a desired signal from a wide spectrum of signals from the receive antenna can be better recovered.

As wireless techniques further advance, a three-phase transmitter/receiver for harmonics rejection has emerged as an alternative in mobile phones. One advantageous feature of the three-phase transmitter/receiver is that the three-phase transmitter/receiver is able to eliminate many undesirable distortions in the wireless network.

One disadvantageous feature of the three-phase transmitter/receiver is that some distortions such as the second order counter intermodulation (CIM2) may still exist in the three-phase transmitter/receiver. As the demand of higher data communications increases, the requirement for even lower distortions in the radio frequency system has become increasingly important. In this scenario, the CIM2 distortion may become a dominant factor for mobile handsets and may cause interference and lead to deterioration in the performance of mobile handsets. Accordingly, it would be beneficial to reduce this distortion level so as to improve the performance of the radio frequency system.

These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by preferred embodiments of the present disclosure which provide an integrated motor drive and isolated battery charger system.

In accordance with an embodiment, a method for reducing distortions of a radio frequency (RF) system comprises configuring a plurality of mixers to convert between a plurality of phase signals and a plurality of RF signals, configuring a first mixer of the plurality of mixers to operate in a six-phase operating mode to reduce the distortions of the RF system, configuring a second mixer of the plurality of mixers to operate in a three-phase operating mode to reduce power consumption of the RF system, and processing the plurality of phase signals and the plurality of RF signals with reduced distortions through configuring the first mixer of the plurality of mixers to operate in the six-phase operating mode.

The plurality of mixers is coupled to a transmitter of the RF system. In some embodiments, the plurality of mixers is in the transmitter of the RF system. Each of the first mixer and the second mixer is coupled to a single-ended power amplifier (PA), and a protected frequency band is located adjacent to a first transmitting frequency of first RF signals generated by the first mixer and away from a second transmitting frequency of second RF signals generated by the second mixer.

The plurality of mixers is coupled to a transmitter of the RF system. In some embodiments, the plurality of mixers is in a transmitter of the RF system. The first mixer is coupled to a single-ended PA. The second mixer is coupled to a differential PA. A protected frequency band is located adjacent to a second transmitting frequency of second RF signals generated by the second mixer.

The plurality of mixers is coupled to a transmitter of the RF system. In some embodiments, the plurality of mixers is in the transmitter of the RF system. Each of the first mixer and the second mixer is coupled to a single-ended PA, and a protected frequency band is located adjacent to a second transmitting frequency of second RF signals generated by the second mixer. An enabled digital pre-distortion algorithm is configured to reduce a second order counter intermodulation (CIM2) component.

The plurality of mixers is coupled to a receiver of the RF system. In some embodiments, the plurality of mixers is in the receiver of the RF system, and a blocker signal is located adjacent to a second or fourth harmonic of a first local oscillator (LO) frequency used by the first mixer, and no blocker signal is located adjacent to a second or fourth harmonic of a second LO frequency used by the second mixer.

A second transmitting frequency of second RF signals processed by the second mixer is higher than a first transmitting frequency of first RF signals processed by the first mixer.

The method further comprises receiving a digital in-phase signal and a quadrature-phase signal, converting the digital in-phase signal and the quadrature-phase signal into a first phase digital signal offset in phase from the digital in-phase signal by 0 degrees, a second phase digital signal offset in phase from the digital in-phase signal by 120 degrees and a third phase digital signal offset in phase from the digital in-phase signal by 240 degrees, through three digital-to-analog converters, converting the first phase digital signal, the second phase digital signal and the third phase digital signal into six phase baseband signals offset by 60 degrees from each other, and producing, based on the six phase baseband signals and a plurality of LO signals, first RF signals processed by the first mixer.

The method further comprises generating three LO signals in response to the three-phase operating mode of the second mixer, wherein the three LO signals are offset by 120 degrees from each other, and each of the three LO signals is of a duty cycle of about 33.33%, and generating six LO signals in response to the six-phase operating mode of the first mixer, wherein the six LO signals are offset by 60 degrees from each other, and each of the six LO signals is of a duty cycle of about 16.67%.

The method further comprises generating a voltage-controlled oscillator (VCO) signal in a phase lock loop, wherein the VCO signal is used to produce the three LO signals in response to the three-phase operating mode of the second mixer, and the six LO signals in response to the six-phase operating mode of the first mixer.

The method further comprises under the six-phase operating mode, configuring the first mixer to mix six phase baseband signals with six LO signals to generate first RF signals, and under the three-phase operating mode, configuring the second mixer to mix six phase baseband signals with three LO signals to generate second RF signals.

In accordance with another embodiment, a method for reducing distortions in a radio frequency (RF) system comprises producing six local oscillator (LO) signals by a LO generator, the six LO signals being fed into a plurality of mixers, configuring a first mixer of the plurality of mixers to operate in a six-phase operating mode to reduce the distortions in the RF system, configuring a second mixer of the plurality of mixers to operate in a three-phase operating mode to reduce power consumption of the RF system, and processing RF signals of the RF system with reduced distortions through configuring the first mixer of the plurality of mixers to operate in the six-phase operating mode.

The plurality of mixers is coupled to a transmitter of the RF system. In some embodiments, the plurality of mixers is in the transmitter of the RF system. Each of the plurality of mixers is coupled to a single-ended power amplifier (PA). A protected frequency band is located adjacent to a first transmitting frequency of first RF signals generated by the first mixer, and no protected frequency band is located adjacent to a second transmitting frequency of second RF signals generated by the second mixer.

The method further comprises configuring the first mixer to generate first RF signals in a first frequency band, and configuring the second mixer to generate second RF signals in a second frequency band higher than the first frequency band.

The method further comprises receiving a digital in-phase signal and a quadrature-phase signal, converting the digital in-phase signal and the quadrature-phase signal into a first phase digital signal offset in phase from the digital in-phase signal by 0 degrees, a second phase digital signal offset in phase from the digital in-phase signal by 120 degrees and a third phase digital signal offset in phase from the digital in-phase signal by 240 degrees, through three digital-to-analog converters, converting the first phase digital signal, the second phase digital signal and the third phase digital signal into six phase signals offset by 60 degrees from each other, generating six LO signals in response to the six-phase operating mode of the first mixer, wherein the six LO signals are offset by 60 degrees from each other, and each of the six LO signals is of a duty cycle of about 16.67%, and producing, based on the six phase signals and the six LO signals, first RF signals generated by the first mixer.

The method further comprises receiving a digital in-phase signal and a quadrature-phase signal, converting the digital in-phase signal and the quadrature-phase signal into a first phase digital signal offset in phase from the digital in-phase signal by 0 degrees, a second phase digital signal offset in phase from the digital in-phase signal by 120 degrees and a third phase digital signal offset in phase from the digital in-phase signal by 240 degrees, through three digital-to-analog converters, converting the first phase digital signal, the second phase digital signal and the third phase digital signal into six phase signals offset by 60 degrees from each other, generating three LO signals in response to the three-phase operating mode of the second mixer, wherein the three LO signals are offset by 120 degrees from each other, and each of the three LO signals is of a duty cycle of about 33.33%, and producing, based on the six phase signals and the three LO signals, second RF signals generated by the second mixer.

In accordance with yet another embodiment, a radio frequency (RF) system comprises a local oscillator (LO) generator configured to generate a plurality of LO signals, a first mixer configured to receive six phase signals offset by 60 degrees from each other and six LO signals generated by the LO generator, the first mixer being configured to operate in a six-phase mode in which the six phase signals are mixed with the six LO signals to generate first RF signals, and a second mixer configured to receive the six phase signals and three LO signals generated by the LO generator, the second mixer being configured to operate in a three-phase mode in which the six phase signals are mixed with the three LO signals to generate second RF signals.

The system further comprises a third mixer configured to receive the six phase signals and six LO signals. The third mixer is configured to operate in the six-phase mode in which the six phase signals are mixed with the six LO signals to generate third RF signals, wherein the first RF signals are in a low frequency band, the second RF signals are in an ultra-high frequency band, and the third RF signals are in a high frequency band.

The local oscillator comprises a voltage controlled oscillator (VCO) configured to generate a VCO signal, and a frequency LO generator configured to produce the plurality of LO signals.

The system further comprises an IQ source configured to provide digital I and Q signals, an IQ-to-3 phase converter configured to convert the digital I and Q signals to first, second and third phase digital signals, first, second, and third digital-to-analog converters (DACs) configured to convert the first, second and third phase digital signals into first, second, and third differential pairs of analog signals, and first, second, and third filters configured to filter the first, second, and third differential pairs of analog signals and generate the six phase signals.

The system further comprises a single-ended PA coupled to outputs of the first mixer.

An advantage of an embodiment of the present disclosure is a hybrid mixer that includes both a three-phase mixer and a six-phase mixer. The six-phase mixer is employed to eliminate or reduce the distortions in a RF system. The three-phase mixer is employed to reduce the power consumption of the RF system.

The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims.

Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale.

The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the disclosure, and do not limit the scope of the disclosure.

The present disclosure will be described with respect to preferred embodiments in a specific context, namely a hybrid mixer for improving the performance of a wireless network comprising a plurality of wireless devices (e.g., mobile phones) and a plurality of base stations. The hybrid mixer comprises a first mixer configured to operate in a six-phase mode to eliminate or reduce distortions in the RF system. The hybrid mixer further comprises a second mixer configured to operate in a three-phase mode to reduce power consumption in the RF system. The present disclosure may also be applied, however, to a variety of radio frequency (RF) systems. Hereinafter, various embodiments will be explained in detail with reference to the accompanying drawings.

illustrates an exemplary wireless network in accordance with various embodiments of the present disclosure. The wireless networkcomprises a base station, a plurality of mobile devices, and a backhaul network. The mobile devicemay be implemented as any suitable end user device such as a user equipment/device, a wireless transmit/receive unit, a mobile station, a notebook computer, a mobile phone, a personal digital assistant (PDA), a media player, a gaming device, a wireless sensor, a wearable device and/or the like. The mobile devicemay comprise a receiver, a transmitter, antennas and other suitable components. Throughout the description, the mobile device may be alternatively referred to as user equipment (UE).

The base station may refer to any component (or collection of components) configured to provide wireless access to a wireless network. The base station may be implemented as a base transceiver station (BTS), a Node-B (NodeB), an evolved NodeB (eNB), a fifth generation (5G) NodeB, a Home NodeB, a macro-cell, a femtocell, an access point (AP), or other wirelessly enabled devices.

As shown in, the base stationestablishes uplink and/or downlink connections (dashed lines) with the mobile devices, which serve to carry data from the mobile devicesto the base stationand vice-versa. Data carried over the uplink/downlink connections may include data communicated between the mobile devices, as well as data communicated to/from a remote-end (not shown) by way of the backhaul network.

The mobile devicemay transmit and receive wireless signals modulated based upon various communication protocols such as such as Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), LTE Advanced (LTE-A), LTE Multimedia Broadcast Multicast Service (MBMS). In addition, the wireless signals may be modulated based upon other standards such as Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), Ultra-Wideband (UWB) and the like. Furthermore, the base station and the mobile device may be configured to implement other suitable wireless protocols.

In some embodiments, the mobile deviceand the base station use a hybrid transmitter and/or a hybrid receiver for performing transmissions. More particularly, the mixers of the hybrid transmitter and/or the hybrid receiver may be configured to operate in multiple (“hybrid”) modes. In particular, the mixer may be controlled to operate as a three-phase mixer or a six-phase mixer. When operating as a six-phase mixer, the hybrid transmitter/receiver consumes more power but may also eliminate or reduce distortions in the RF system. When operating as a three-phase transmitter, the hybrid transmitter/receiver consumes less power.

The three-phase operation may be performed in situations where distortion requirements are relaxed, and the six-phase operation may be performed in situations where tight distortion requirements are needed. The distortion requirements for a transmission may be determined based on whether a protected frequency band is adjacent to the transmitted frequency of the mixer. When the frequency band is not adjacent to the transmitted frequency of a mixer, the distortion requirements are relaxed. The three-phase operation may be performed in the mixer for reducing power consumption. Throughout the description, the six-phase operation may be alternatively referred to as the six-phase operating mode. The three-phase operation may be alternatively referred to as the six-phase operating mode.

illustrates a block diagram of a UE shown inin accordance with various embodiments of the present disclosure. The UEmay be implemented as a mobile phone, but may be any suitable wireless devices as described above with respect to. As shown in, the UEincludes a transmitter, a receiver, a memory, a processor, an input/output deviceand an antenna. It should be noted for simplicityonly illustrates relevant components of the UE. The UEmay comprise other suitable components. Furthermore, whileillustrates one element (e.g., one processor), the UEmay accommodate any number of such elements.

The processorcan implement various processing operations of the UE. For example, the processorcan perform signal coding, data processing, power control, input/output processing and the like. The processormay include any suitable processing or computing devices configured to perform one or more operations. For example, the processormay include a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array, an application specific integrated circuit and the like. The memorymay be implemented as non-transitory memory storage.

The transmitter (TX)is configured to modulate data or other content for transmission by the antenna. Prior to feeding signals to the antennafor transmission, the transmittermay receive a baseband digital signal, convert the baseband digital signal into an analog signal, filter the analog signal, up-convert the filtered analog signal to a radio frequency signal, and amplify the radio frequency signal. The amplified radio frequency signal is transmitted by the antenna.

The receiver (RX)is configured to demodulate data or other content received by the antenna. The receiveris configured to receive the RF signal from the antenna, amplify the RF signal, down-convert the RF signal to a baseband frequency analog signal, filter the baseband frequency analog signal, convert the filtered baseband frequency analog signal into a baseband digital signal. The baseband digital signal is sent to a baseband processor for further processing to output voice or data. The receivercan include any suitable structures for processing signals received wirelessly. The antennacan include any suitable structure for transmitting and/or receiving wireless signals. The same antennacan be used for both transmitting and receiving RF signals, or alternatively, different antennascan be used for transmitting signals and receiving signals.

It is appreciated that one or multiple transmitterscould be used in the UE, one or multiple receiverscould be used in the UE, and one or multiple antennascould be used in the UE. Although shown as separate blocks or components, at least one transmitterand at least one receivercould be combined into a transceiver. Accordingly, rather than showing a separate block for the transmitterand a separate block for the receiverin, a single block for a transceiver could have been shown.

The input/output devicesfacilitate interaction with a user. The input/output deviceincludes any suitable structure for providing information to or receiving information from a user, such as a speaker, a microphone, a keypad, a keyboard, a display, a touch screen and any combinations thereof.

The memorystores instructions and data used, generated, or collected by the UE. For example, the memorycould store software or firmware instructions executed by the processor. The memorymay be implemented as any suitable volatile and/or non-volatile storage and retrieval devices such as random access memory (RAM), read only memory (ROM), hard disk, optical disc, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card and the like.

illustrates a block diagram of the base station shown inin accordance with various embodiments of the present disclosure. The base stationincludes a processor, a transmitter, a receiver, one or more antennas, and one memory. The processorimplements various processing operations such as signal coding, data processing, power control, input/output processing and the like. The processorincludes any suitable processing or computing device configured to perform one or more operations. The processormay be implemented as a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array, an application specific integrated circuit and the like. The memoryis non-transitory memory storage.

The transmitterincludes any suitable structure for generating signals for wireless transmission to one or more UEsor other devices. The functions of the transmitterare similar to the functions of the transmittershown in, and hence are not discussed herein. The receiverincludes any suitable structure for processing signals received wirelessly from one or more UEsor other devices. The functions of the receiverare similar to the functions of the receivershown in, and hence are not discussed herein. Although shown as separate blocks or components, the transmitterand the receivercould be combined into a transceiver. The antennaincludes any suitable structure for transmitting and/or receiving wireless signals. Whileshows a common antennacoupled to the transmitterand the receiver, more antennascould be employed depending on different design needs. The memorymay be implemented as any suitable volatile and/or non-volatile storage and retrieval devices.

illustrates a block diagram of a first implementation of the transmitter shown inin accordance with various embodiments of the present disclosure. In some embodiments, the transmittermay be used in the UE shown in. Alternatively, the transmittermay be used in the base station shown in. Furthermore, the transmittermay be used in any suitable radio frequency systems.

As shown in, the transmittercomprises an IQ source, an IQ to 3-phase converter, digital-to-analog converters (DACs),, and, low pass filters (LPFs),, and, a 6-phase/3-phase mixer, variable gain amplifiers (VGAs),,,,, and, transformers,, and, switches,, and, power amplifiers (PAs),,,,, and, a filter, an antenna, and a frequency synthesizer.